What describes a material that can change its properties in response to environmental stimuli?

A material that can change its properties in response to environmental stimuli is best described as a smart material. Smart materials are specifically designed to react dynamically to external conditions such as temperature, pressure, light, moisture, or electric and magnetic fields. This ability to adapt creates functionalities that are not present in traditional materials, allowing for innovative applications in various fields including engineering, robotics, and consumer products.

For example, some smart materials may become more flexible when heated or can change color in response to different temperatures. This adaptability makes them suitable for applications that require responsiveness to changing conditions, which is a defining characteristic of smart materials.

While thermochromic materials indeed change color based on temperature, they are a subset of smart materials focused on color change. Conductive materials have fixed electrical properties and do not inherently change with environmental stimuli, and biodegradable materials refer to the breakdown process due to biological factors rather than changes in their properties. Thus, the broader category of smart materials encompasses a wide range of responsive behaviors, making it the most appropriate answer.